Abstract: To validate the combined atmospheric radiative transfer model(CART) code on calculating the scattering of atmospheric molecules and aerosol particles, comparisons of CART scattering results (including the single scattering radiance and multiple scattering radiance) to the moderate resolution atmospheric transmittance and radiance code (MODTRAN5.0) and discrete ordinate radiative transfer (DISORT) model were made, respectively, on the wide range of observation zenith angle, solar zenith angle, the differ of observation and solar azimuth angle, the asymmetry factor of scattering phase function. The results show that the relative percent difference is less than 10% mostly, 15% at maxmium on single scattering radiance, and less than 2.5% on multiple scattering radiance. CART have a good calculation precision and efficiency on atmospheric background radiance calculation including multiple scattering.